It is well known in the field of heavy hydrocarbon production to upgrade the produced hydrocarbon from a hydrogen-deficient state to an upgraded product having greater commercial value. This full upgrading is commonly achieved by fractional distillation and hydroprocessing to produce saleable products like synthetic crude oil.
One primary category of upgrading is hydrogen addition, in which molecular hydrogen is reacted with the heavy hydrocarbon to add hydrogen to the heavy hydrocarbon's molecular structure and convert it to a higher value product. Three forms of hydrogen addition are commonly practiced in the Canadian heavy hydrocarbon industry, namely hydroconversion, hydrocracking and hydrotreating, all of which employ catalysts to drive the necessary conversion reactions.
However, the construction and operation of full upgrading facilities at the hydrocarbon production sites they service is well known to be extremely expensive, and would generally produce a product that is over-qualified to be shipped by pipeline. The conventional alternative has been to blend the heavy hydrocarbon at the production site with a refinery-sourced diluent such as a lighter hydrocarbon, which decreases the viscosity and increases the API of the product to a level at which it can be pipelined to a refinery for additional processing. By using diluent to reduce product viscosity/density and enable pipeline transportation, this commonly employed solution generates a continuous fluid flow loop between the production site and the refinery, with the refinery sending diluent to the production site for blending with the heavy hydrocarbon, and the production site sending the blended product back to the refinery for processing, with the diluent commonly being recycled and fed back into the process.
While the benefits of this conventional solution are obvious, it is also known that the use of diluent introduces certain disadvantages. For example, diluent is used in significant volumes, resulting in high freight costs for shipping the diluent. Because the diluent is piped to the refinery along with the heavy hydrocarbon as part of the blended product there is a necessary increase in the required pipeline volume and thus the costs involved. Also, the cost of diluent itself can be dissuasive. While on-site full upgrading would potentially provide a solution to these disadvantages by eliminating the need for diluent altogether, this would require the significant expense of a catalyst supply and in some cases an on-site hydrogen molecule production facility such as a steam methane reformer. In traditional on-site full upgrading processes, coke or asphaltenes can also be rejected on site, which can waste hydrocarbons and potentially create site disposal issues. This alternative thus manifests further disadvantages.
What is needed, therefore, is a means to prepare produced heavy hydrocarbon for transport to a refinery for the processing necessary to generate saleable products for the marketplace, but a means that represents a costs savings over the conventional solutions.